Level of robot autonomy and information aids in human-robot interaction affect human mental workload - an investigation in virtual reality

In future work systems, humans may interact with scalable industrial robots. In a virtual reality simulation study, human mental workload effects were analyzed in human-robot interactions (HRI) with variations in design requirements regarding human factors and ergonomics (HFE) as well as occupational safety and health (OSH). Each of 20 participants performed his/her own task while interacting with two virtual robots in a manufacturing environment. Results on task performance indicated relative lower human mental workload when robots acted on lower level of robot autonomy (lower LORA) and the human operator was informed about upcoming HRI by multi-modal signaling (Information Aid 'on'). However, this pattern of workload reflected in performance measures, was not reflected in mental workload ratings. Hence, compensational adjustments in operator performance were assumed. It was concluded, that a combination of less autonomous robots and multi-modal feedback result in relatively less operator distraction from task performance and, thus, less impairment in operator workload. HFE and OSH may improve when HRI is audio-visually indicated and robot activities are adapted to human operator task requirements (low LORA). Therefore, results have the potential to inform future design of HRI regarding HFE and OSH at different workplaces in industry and services.